There are dangers in being proudly. Sure, it's okay to talk about winning a contest or how you performed a great act of Shakespeare.
However, sometimes you can get into thinking that you're the best at everything and then begin to feel higher and more important than other people.
You begin to crave for attention and forget about what God has done for you. Below are some signs of self-exaltation:

You look at other people inferiority, which is, thinking that people fall short of you.

You think of how popular and cute you are. Soon your only devotion isn't to God, but only to improving your looks and social/church status.

You brag about your church position. You also abuse your job, utilizing it to gain control of people or tease them.

You use prayer only to gain attention from other people. It's good to pray but if you're just praying to get attention from people or expect a greater reward from God, get real!
That is the kind of situation when you pray proudly, when you use articulate language to gain attention in your prayers.

These are some signs of being proudly. These are dangerous because you will not only be shunned by other people and cause God to be angry, you will be abased--which is, brought low. If you know you're acting in this manner please stop and get yourself right.
If you don't then you will be seen as a fool, and you don't desire that kind of reputation. So please, be humble.